Tag: Pregnancy

Heads it’s a Boy, Tails it’s a Girl

January 8, 2018

The CBC recently published a story promoting a urine-based test to determine the sex of a fetus during pregnancy. Although the article claims the kit has an 80-92% accuracy based on three studies, no citation was provided and there was clearly no assessment of the quality of these studies (if they exist). While this should have been the focus of controversy surrounding the article, a controversy was instead manufactured surrounding the name of the product: GenderSense.

Remy Warren GenderSense
Founder Remy Warren and her GenderSense. Retrieved Jan. 2018 from: https://www.therecord.com/news-story/8035054-kitchener-woman-counting-on-curiosity-of-expecting-parents/

Rather than relying on a qualified OB-GYN to discuss the nature of this sort of testing, the author interviewed a sociology professor from Wilfred Laurier. While the professor pointed out the issues in conflating gender as a social construct and sex as a biological trait (and I mean – come on – it’s not 2012, people), there was no discussion contextualizing the product medically. When is sex normally determined via ultrasound? How does this time frame and accuracy compare with the proposed product? How will this knowledge empower the consumer to make decisions going forward? Perhaps the company could have avoided this distraction by naming the product SexSense. Then again, that name sounds more like something you’d see in your spam folder rather than a pharmacy.

SexSense
The sixth sense?

Like most journalists, I don’t know a damn thing about reproductive health. Unlike many journalists, however, I am concerned with the accuracy of scientific and medical claims. So, time to learn a thing or two.

First, we should establish why sex determination is important. The most obvious answers are for social reasons: preparing psychologically, shopping, religious reasons, and even just plain curiosity. While we can debate the validity of these reasons and their potential consequences, there are also good medical indications. There are numerous sex-linked disorders that a fetus could be predisposed to, either necessitating prompt medical intervention, or potentially forming part of an informed decision in the choice to terminate a pregnancy. The ethical considerations are vast and there is no way I’m touching those. So, how do we determine sex?

As it turns out, prenatal biological sex is not trivial to determine. Although there are many exceptions – especially in cases of genetic anomalies and divergence between genotype and phenotype – sex is generally best determined by identification of the sex chromosomes (XX vs. XY). The gold standard test is a sampling of the chorionic villi, however, this procedure does not come without risk, including a very small increased risk of miscarriage. Amniocentesis is an alternative test that comes with similar low, but quantifiable risks. As a result, secondary measures are preferred, such as the examination of physical traits or testing of cell-free fetal DNA, which are both rather accurate and safe.

How accurate are these measures? The answer is: it depends on how far along the pregnancy is. Obviously it would be great to know at the time of conception, but the unfortunate reality is that we don’t live in a world where techniques like Chinese Astrology are anything more than chain email content or Reader’s Digest filler. Instead, we have to wait for the expression of traits that our science-based tools actually measure.

In the case of ultrasound – while generally inaccurate in the first trimester – the accuracy of sex determination greatly improves between weeks 11 and 13 (nearing 100% if anomalous cases are excluded). While the procedure is evolving with newer, higher resolution imaging technologies, it has historically relied on a simple premise: is there a penis? Obviously, the modality is very dependent on physical characteristics, which do tend to vary.

Trump
A 217th Trimester Fetus. Retrieved Jan. from: http://i0.kym-cdn.com/photos/images/original/001/187/563/38d.jpg

Cell-free fetal DNA testing is a bit more interesting. This is fetal DNA circulating in maternal blood that is sampled with a blood test. The obvious limitation is the requirement for enough fetal DNA to be in circulation, which most certainly is not the case at the moment of conception. A recent review indicated that the test was unreliable if performed before 7 weeks of gestation. Interestingly, the authors also concluded that urine testing for cell-free fetal DNA was unreliable. Is any urine testing reliable?

Scouring the literature, there were no conclusive studies that supported any form of urine testing for sex determination. Despite this, many products south of the border have made bold claims regarding the efficacy of their urine tests. Experts appear to conclude that these test are entirely bogus.

One particular product bears a remarkable resemblance to GenderSense; IntelliGender claims to be the “first in-home Gender Prediction Test.” Let’s compare the products:

A Comparison of GenderSense and IntelliGender Claims 
 GenderSense Claim IntelliGender Claim
Type of Test Urine-based prenatal sex determination Urine-based prenatal sex determination
 Alleged Accuracy  80-92%  80-90%
Alleged Evidence Three Studies Internal lab trials plus two independent trials
 Colour Indicator Orange or yellow for a girl, green for a boy Orange or yellow for a girl, green for a boy
 Earliest Claim of Efficacy  10 weeks 10 weeks
 Wait Period After Mixing  About 5 minutes  5 minutes
 Retail Price  45 USD  Around 40 USD

While these are some pretty striking similarities, it’s worth noting that there is one big difference between the two products; new to the market, GenderSense has yet to be on the receiving end of legal action for selling a misleading and dangerous product. That’s right; IntelliGender was found to rely on lye, aka Drano, aka sodium hydroxide – a caustic chemical that was likely the cause of multiple explosions. Ultimately, IntelliGender was ordered to pay penalties in the amount of $250,000 for marketing a product attorneys for the city of San Diego called “nothing more than Drano in a pretty box.” While there appears to be no published evidence of efficacy, experts concluded that the test results were “about the same accuracy as a coin toss or random guess.”

Does GenderSense have anything better to offer? The purported studies might have the answer, but I won’t hold my breath for their release. After all – as with IntelliGender – GenderSense’s founder Remy Warren does not possess any formal scientific or medical training. Business as usual.

Because the product does not claim to treat a medical condition or make a diagnosis, Health Canada has announced that it will not pursue regulating the device. They make a fair point, but who is to regulate the science of this pseudo-medical product? What happens if parents rely on this information to make medical decisions? Regardless of the implications of knowing the sex of a fetus, the implications of making the wrong assumption could be dire.

It would have been nice if these issues were raised by the CBC. Then again, if it weren’t for bad science reporting, I wouldn’t be learning so much about fetuses.

Thanks to Dr. Terry Polevoy for his investigative work and commitment to Canadian health issues. Remy Warren was contacted prior to the release of this article, but I have not yet received a response.

 

Chiropractors and the Fetus

December 25, 2017

While chiropractic care for infants has generated substantial controversy (and rightly so), there has been little criticism regarding chiropractic prenatal care. Back pain is, of course, common during pregnancy, but – although it is reasonably safe – there isn’t good evidence that chiropractic care can be effective during pregnancy. Chiropractic care for back pain, however, isn’t the most egregious service chiropractors offer pregnant women. What is? Chiropractic care for breech presentation of the fetus.

Breech positioning occurs when a fetus is positioned bottom-first, rather than the common presentation of head-first. It’s not particularly common and the best course of action is generally to perform a caesarean section. As caesareans are not without side-effects, it’s understandable that expectant mothers would like to pursue alternatives. Enter, chiropractic.

Breech Baby Position
Breech Position. Retrieved Dec. 2017 from: https://en.wikipedia.org/wiki/File:Breechpre.jpg

In a 2009 article published in Canadian Chiropractor, CMCC graduate John Minardi promotes what is known as The Webster Technique – a technique “specifically designed to detect and correct for pelvic subluxations that occur in a pregnant patient.” Of course, we know that’s bullshit because subluxations don’t exist, but what does he claim is the purpose of this approach? To “improve birth outcome,” naturally.

Luckily, CMCC graduates are often more scientific than their US-educated counterparts. They may not all understand science, but they at least understand the importance of science. In his article, Minardi (who teaches the technique) cites a single paper supporting the approach: “The Webster Technique in a 28 Year Old Woman with Breech Presentation & Subluxation“.

The paper is exactly what it sounds like; it’s a case study that followed an individual woman with breech presentation who received chiropractic care in the form of Webster’s technique. Her follow-up indicated that the fetus re-positioned to the vertex (head-down) position. The study concluded – based on this alone – that Webster’s technique should be offered to all patients instead of a caesarian section. This is an interesting conclusion considering that spontaneous correction occurs in the majority of cases regardless. This study portrays mastery only of regression to the mean and should be cast adrift with the multitude of chiropractic case studies making unsubstantiated claims.

So exactly how pervasive is this unsubstantiated technique in the business of chiropractic? Every word in this sentence links to a London, Ontario Chiropractor advertising Webster’s Technique. Good job, none of you. Of course, there is no firm data because there is no oversight of unscientific chiropractors in Ontario, but – based on 29 chiropractors identified online in London offering the technique and using data from the CCO – at least 21% of chiropractors in London sell this bit of pseudoscience.

One of the most prolific chiropractors offering the technique is London’s own B.J. Hardick (recently suspended for illegal blood tests). His YouTube video describes a 32-week pregnancy adjustment that he seems rather confident in:

B.J. Hardick Webster
Retrieved Dec. 2017, from: https://www.youtube.com/watch?v=XP4VceZsZgI

If this is a claim of 100% efficacy, disclosure of the supporting data would certainly be interesting. Regardless, practitioners who claim Webster’s technique is effective at turning breech fetuses have put themselves in a precarious position; a well-defined clinical trial with objective measures of outcome would be easy to run at a low cost and possibly low risk. Yet – after decades of promotion – all we have are useless case studies and useless surveys.

As it stands, the promotion and practice of Webster’s technique as a remedy for breech presentation is quite possibly patient abuse, yet offerings like these appear to be endemic to chiropractic in Ontario. A little bit of reservation from chiropractors offering unsubstantiated techniques would be great. Widespread adoption of a culture that respects and understands science would be even better.